Disc drives are common data storage devices. A typical disc drive includes a rigid housing that encloses a variety of disc drive components. The components include one or more discs having data surfaces that are coated with a medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor that causes the discs to spin and the data surfaces of the discs to pass under aerodynamic bearing disc head sliders. The sliders carry transducers, which write information to and read information from the data surfaces of the discs.
To increase recording density, it has become desirable to reduce the fly height over the disc. During disc drive operation, serious damage to the disc and a loss of data can result during lowered fly height if particles were to become present in the head disc interface (HDI). The primary source of particles in the disc drive is a result of head to disc contacts. A secondary source of particles in the disc drive is the origination of particles in sub-assemblies during manufacture. Other sporadic sources of particles are ramp load and unload events of the actuator mechanism, inner diameter and outer diameter slams, outgassing of certain components at high temperatures, and the limited exchange of particles through the breather hole. The particles in the disc drive's enclosure that become present in the HDI can cause performance problems such as media defects, thermal asperities, stiction, or catastrophic drive failure. Further, particles in the HDI can reach the trailing edge (TE) of the slider and damage the sensitive transducer which can prevent further read/write operations.
Current data storage systems rely on capturing the particles in the disc drive through the recirculation filter. For example, recirculation filter efficiency is governed by its location, orientation, inlet/outlet geometry, filter distance from the disc edge apart from its size, disc spindle speed and disc size. Due to the complexity in the design process and various trade-offs, it is not possible to clean the disc drive by the recirculation filter to the extent required due to the increasing sensitivities of the HDI to smaller sized particles. The increase in sensitivity of the HDI is caused by decreasing head disc spacing budgets (HDSB) and increasing mean time between failures (MTBF) requirements. It is relatively difficult to capture sub-micron particles since they tend to follow the airflow and are affected significantly by the turbulence levels in the disc drive. There is a need to improve the ability to capture sub-micron particles in data storage systems.
Embodiments of the present invention provide solutions to these and/or other problems and offer other advantages over the prior art.